Method in the madness
Polonius:
What is the matter, my lord? Hamlet:
Between who? Polonius:
I mean, the matter that you read, my lord. Hamlet:
Slanders, sir; for the satirical rogue says here that old men
have grey beards, that their faces are wrinkled, their eyes purging
thick amber and plum-tree gum, and that they have a plentiful
lack of wit, together with most weak hams; all which, sir, though
I most powerfully and potently believe, yet I hold it not honesty
to have it thus set down, for yourself, sir, shall grow old as I am, if
like a crab you could go backward. Polonius:
[Aside] Though this be madness, yet there is method in't.
Our expression, "There's a method in the madness," derives from this comical scene, although we've tampered a bit with the phrasing [compare THE BETTER PART OF VALOR IS DISCRETION]. The politic Polonius, convinced that Hamlet is truly mad, nonetheless recognizes in his speech some "method"—that is, a kind of artfulness and order. Whether he appreciates Hamlet's point is unclear.
Polonius diagnoses Hamlet's madness as a form of "love-melancholy," considered a full-fledged disease in the Renaissance. The old man has ordered his daughter Ophelia, Hamlet's girlfriend, to refuse to see the prince or receive his letters, and Polonius now concludes that such refusals have resulted in Hamlet's sorry state. Hamlet, however, only puts on a show [see ANTIC DISPOSITION].
As a sort of revenge on Polonius, whom he recognizes as one of King Claudius's numerous spies, Hamlet plays the "satirical rogue" and enumerates the debilities of age, pointedly making fun of Polonius. In the process he borrows one of Polonius's own rhetorical tricks: occupatio, or paralepsis—pretending to pass over or contemn something while actually stating it openly [see MORE MATTER WITH LESS ART].